Pressurized dry air which is relatively free from particulate matter and oil is required for many industrial uses. Moreover, in an industrial context the source of air to be cleaned and dried frequently exists at a prohibitively high temperature for efficient use of many desiccants. Still further, there are many installations where the source air contains a high percentage of water so that if only absorbent media are used for drying the air, this necessitates frequent replacement of the water saturated absorbent media to maintain filtering efficiency which is both expensive and time consuming.